1. Field of the Invention
The present invention is broadly concerned with an improved method and apparatus for the adhesion testing of coherent flowable materials such as doughs. More particularly, it is concerned with such a method and apparatus for the accurate, direct measurement of adhesion or "stickiness" of such materials, while eliminating interfering factors such as the flow and coherence strength thereof.
2. Description of the Prior Art
Instruments for measuring adherence of different types of adhesive materials are commercially available. These devices normally include a probe which is compressed against the surface of the material being tested, followed by withdrawal of the probe at a fixed speed. The force required to separate the probe from the adhesive surface is recorded as a measure of stickiness or adhesion.
However, instruments of this type are not directly applicable for adhesion measurements of flour doughs or other types of coherent materials. When the probe is brought into contact with the surface of a sticky dough, and then pulled away, the dough will often stick to the probe and undergo flow. As the plunger is continuously withdrawn from the sample, the dough stretches and flows, and eventually breaks at a point midway between the probe and the dough mass. As a result, the coherence force that accounts for dough strength holding the dough together is actually measured, rather than stickiness or adherence.
Doughs exhibiting undo stickiness can present a very significant problem to commercial bakers. A very sticky dough can over a relatively short period of time completely clog dough handling equipment, to the point requiring frequent shut-down and clean up of the equipment. These problems are particularly acute with certain recently developed, disease-resistant wheats having a 1B/1R translocation. Some flours derived from such strains give very sticky doughs, even when the flour is given optimum mixing time and water absorption during dough formation.
As a consequence of these developments, commercial bakers are in need of data accurately reflecting the stickiness or adherence characteristics of doughs made from different types of flours, so that informed decisions can be made about the desirability of purchasing specific flours. Despite this need, however, there has heretofore been no accurate means of measuring adherence of coherent flowable materials such as doughs.